I'm using a Western Digital 3TB hard drive on a Windows XP SP3-based Lenovo T410i. I've used the disk for some months without any problems but all of a sudden the disk shows as being unformatted - Windows asks if I want to format the drive.

Of course, I don't want to format the drive as there's lots of information on there which I cannot afford to lose.

As I know for sure that the drive is formatted, is there any way I can flag this so that Windows can access it?

3 Answers
3

Try chkdsk /F, I've rescued a drive with that before, with no data loss.

Of course, while you're waiting for that to finish, the obvious answer is "Restore from your latest backup". If you can't afford to lose your data, you definitely shouldn't entrust it to a relatively fragile hard drive!

Actually, I would specifically leave off the /f. Using that switch will cause chkdsk to try to fix anything it deems an error, without prompting you. I would recommend first running it without the /f switch to see what it finds, and then, maybe use it if chkdsk indicates that it knows what it's doing. Otherwise, if you use the switch first, right-off-the-bat, then chkdsk could end up messing things up even more. (That said, you'll need to find some more advanced tools if chkdsk can't handle the corruption.)
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SynetechMay 23 '11 at 19:56

Actually no. The 'ideal' thing to do is to make a full image of the disk with something like DD before you go any further. (if you can't, well do the next bit anyway).

Next, check if you can access the file system with a linux livedisk with NTFS3g, ubuntu's a good common one, but nearly any disk will work - these sometimes manage to open drives that windows fails to open. If that works, recover the essential files before you do anything else, better yet, copy all the files out...

Once that's done attempt to recover the old partition table with testdisk. If it detects the old filesystem, its all good, and you can run the recovery process. else, you'll have to reformat the drive and copy the dara back into place

Really? Image a 3TB drive? On to what? A spare 3TB drive that’s just lying around? It must be nice to be rich…
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SynetechMay 20 '11 at 12:21

2

that's why its the 'ideal' thing and optional. The rest of it works in almost every situation i've tried it in short of physical damage
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Journeyman Geek♦May 20 '11 at 12:24

@Synetech inc; If your data is very valuable to you, why wouldn't you spend money to make sure you have the best chance of recovering it? Once everything is over you can use your now spare 3TB drive for backups.
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PhoshiMay 21 '11 at 10:30

@Phoshi, I'm pretty sure that 3TB drives are still quite expensive. Most people probably don't have a budget for two. Besides, I doubt that most people have that much "important" data; of 3TB, only a couple of GB is truly important, irreplaceable stuff, and the rest is large stuff like CD and DVD rips, installed apps and games, or downloaded files which can be replaced.
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SynetechMay 23 '11 at 12:40

@Synetech; You're probably right, but the asker is in a bit of a tough position, having a 3TB drive and no filesystem access. Either the data is as critical as they say, and buying the drive is a neccesary expense, or it isn't, and they take the risk. Obviously if they'd backed up beforehand they wouldn't need 3TB of space, but they didn't.
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PhoshiMay 23 '11 at 12:49

Rather than being a problem with your hard disk itself, this could be a problem with a virus on your hard disk or windows. I used to face a similar problem with my pen drive previously when I was on Win XP. If its possible try and access your hard disk using linux and delete the autorun and executables on the hard disk. Then reformat your PC and try again. That worked for me.